SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8ef4441ddc21408b15e5f36d6961a3994b060a110c940cb5f4502c3f31ec250' 
  AND token = 'WNeJ2O/6qZaNhHIxZAnkqCwmS/xaNEA7+HAGTxSpHHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}