SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '545e13b4d1551e02eba82fadf6c10c8d8e44fe0f8fbff195649976c494cb2a17' 
  AND token = 'k/GhgJgXzahluepTgjH90pFa0gg5xvCSBDPK64D6/UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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