SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6353646efd75466a1cd3d07d60031fce432f1ef3a258e2d4bbfeb3a0fcc1221' 
  AND token = '4Jg84EwOq53b8Gyni7AZ/PtGRNCP57hH5Cu9lVUsnCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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