SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '859a5bde1fcbf45f40634d7c4bb61fb4aa5dca02010ca7b489215f3a02f709c9' 
  AND token = 'sgndZ8+ZnNdvgp8lXxxgYXRO3lvFNnufr6/U+yMVQec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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