SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ddb1c00323aba1da884bbfa477d030f0a9d5301b64daeb6a4ea3acf4bcd27d5' 
  AND token = 'LqPQ3HobD8YJx6HL4sAWXcL8cKzhpMA8/PK2MPqsVPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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