SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa306245bd7ae544ab6f66752dbe44dfd30c5dc12b5ae12d04e3e85e40b7a7b2' 
  AND token = 'hdmNdlejGYvaM6aRMDkBDBLKNMGhaGwUYDMbcB+mwFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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