SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '874260b7c1516aa88881d32541f22ba8ec8892da48df5c67c1d65f6cb7863e2f' 
  AND token = 'E7Sk/ETtQBpVQDBzvMj2N+9Yu8DyfGsnAOdGqYpcFXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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