SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '459573641b330b3a03259a14602c5b74573ef3751af36188cd1b808c822cca28' 
  AND token = '5CI23MSSrNz8fIx7QMAEWke0sv0xzKIlGi/MxckBbro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00112

JSON explain

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