SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fe43942ea7566013f7addda4e23562c0789801c25748e901fda6de1bf2d5066' 
  AND token = 'dfPN5oyKvGxkQrN3GsfO5PJFZVrt5xkkcA/R+ghqKyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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