SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3de9560d809154f500efade5138c44195795a091a7d7d248871f6d53fe19339d' 
  AND token = '+J7hY6NOwpZT5YAxTFX9y0w9fSIp2808WEL8bg8GR7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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