SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '196c21060f08d6c583f2c4bb5df45a28ae54db75d17d79a2dbdd5724bcf14f16' 
  AND token = 'WRol2bc3U50hqoJ5a3RX028Bq8Im5RKOufkqdFlsiCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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