SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17beb0b3cc9c40e17335802084b866d033961d5f2c7c67224ede01cfcab61911' 
  AND token = '/BLXe7k812l7lhwedQANdN8vOHLK6m+M20hfhT75j0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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