SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efd1b3ab840114d93d72751a77d87b1fe5de217624b74cbe082d876f6c611690' 
  AND token = 'tmUTafWfIAvw4Y0uKIqzQ5TwiBUdYp8zff52B1CPudg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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