SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f75c6681eedebab0dccb814ade56dc343943d27f2d4c43bc5b4bfdb8f05d0b06' 
  AND token = 'zE0vVAlTiUnFZjHcoTazUDhrorMZ2HbfsAa1378rWik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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