SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5683fb339496ec0ae14751b2a8cd978c44599f8ed8f03f2a7bb1d47a471a7e35' 
  AND token = '3qDDbK/qPnW5REvHu/n7vD7ZP2irwC2nikC7+4+gNzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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