SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9d4546275ffb782c15d166b4658f1b82b21f41e44f9187faa1f5099c09a49ff' 
  AND token = 'bTBnDg5yibz8rU7SgwPYUD1Z9pOLBoKhtjBXsYVPBKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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