SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de08203d223fbbee8b750199f52751b7e957a74ee4588862a4ed3db7674fd2d0' 
  AND token = 'zLPunPYwXwYN1KNAz4ay+QuS8w7E+jbHALO1gqu0jvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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