SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8536a30362f86888d39adf4a3b230177fa3ff3b2bd52cb362084af3175aa37eb' 
  AND token = 'f+9g/8S+mkOIHcer3DebTBSoosy1GNbavMqCW0+ZEFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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