SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31229122e5e927a50df690e677b4567f0da9cd067c0aac580d4ccbd2d07ebf1d' 
  AND token = 'Sub7PAgPb8/4fCnjdF0o6YrX8mZZXQ3ZKPWwFnt+qGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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