SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa1b2ddcf6986c575a413942dd4b3dfff4966bccd452c242519f129416dda072' 
  AND token = 'IKNiOObi0neyWeMIU8e2hPEUlYnzlC4dO0hnpfcvkZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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