SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78a7bd680c4838aade9516f22bb37b5893d3c18ca635cc8b453a052854f97868' 
  AND token = 'U+Dw2s6CnMhSrsVY8yTwCQjd/wSlc8y1QjWLHzOe+VA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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