SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce1f8cca88e464d287bcba632992934b08e7d552dc97182c6185824132a42e40' 
  AND token = 'oytLVEGYnrfnesO0CcTOcpQ9L3ydzEnNWE9yH80ij8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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