SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d212f1c0bf2942368ce34ca8d5c1dc52d2324fe2dbf7fac5f38203d5b4d4257' 
  AND token = '7wDqdGnqqFayMysVHhumDfX96ujjHRflHFaUnxi83no=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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