SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5db98ee7614215be22bee86704b8a7b419dd79216cdd04a94aeeb1089ffdf67e' 
  AND token = 'phlY+ymWM7IKpDVHb0G3wuZgfZrDm3iGL/isjSrsiXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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