SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9df34908d0f567257836b5e6f414adbcca7ea501a0ba948a2e0d6f06eb4279cd' 
  AND token = 'thQm7W3Anx+linUrS15q7cVUuzJMtpJFAoRsHXWMyEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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