SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1558da7d90b5c6840185cb0bb4ed014f0d640ad47d1c5a975544ffb78679ac06' 
  AND token = '0w+jVVYJpZdg1uRDrmwWzXCWoLmID81bsRIdSQ/QY4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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