SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd186e0731a718f09bd845a93b01e0d08448b5794d33bc1fc2bf262d0647be0a3' 
  AND token = 'iob7DB/8W3zTf4KuwMjl8ygrY+l+Xhk/gTZRStzfdxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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