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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d1b29d957aefd6f753c5008a4f85dad7219487440f1ddf453b3fccd41dbf15a' 
  AND token = 'Vr5hWFsJZKXvXTjQ5MYMSsX5WNePx2gzzn+epWcz8Ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}