SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f03dddffc2c7c10eed73a3c6bb21589c49398dc903077b08f7d81941a7ea04eb' 
  AND token = 'DBZahR0AFtmn/sWvhuzjwMsPGISV34O1YvnQJDdKW+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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