SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd712d1eb188549cadb8106f192e075aa02a57f8ff76758b28fbce62a0aad2231' 
  AND token = 'F6+eM17RT09JYQaLGEndhvKR0iRDbS35oQR9vsvKKaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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