SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cef1a7943c996afb43b1fa6f0bf203416de3236f60995bd997a7c85777c3eef6' 
  AND token = 'NnX0VXjq5zjpahYXInHQ22Vqufgb7ZurO6Xjhu9SJAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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