SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f0fb48719800a902b259493ae2721b79823ebcfeb5ba7e7ddc48d7f301f4b66' 
  AND token = 'BExfYyDz9cKk2ZLbzS/oL/aP0hsHwxymh21hhqFdJsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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