SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c97d76a96164deb1ef36cec83df7704426f8f082f80902e57d4f8275538da12' 
  AND token = 'MAAfbgb5VKbWztIIRzH5MY1T03i1OU5rX/PUrMuMK6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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