SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea912d66fc6ea9bbf6c7bb691cc95818f131313642144beafa573c011ff64dc7' 
  AND token = 'UYKtLAK/oNmDcw3WPZUh16THT0vGB3gR/0rTOCgTHqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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