SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '926072881b9f8f5821e666d962c9716ef2c24384067c4c9f431bcd03c34ece55' 
  AND token = 'KEM/q6giAiCUJsVTpUDYKHTSAiWOBn9wHdxxon3wLJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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