SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '365e18174c5387b9f83845a14b5dc01e6296b82f784b59585a6d709bdb7e268e' 
  AND token = 'bFvTg/vh2eZoYZf9tDEw284Z5cmhL+7NxMzB/NJbh4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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