SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '183b64b0183612114da137097f87c2ee81a1415a4099a83acac12c166d0d3780' 
  AND token = 'cfO0ogYx8VmsuCRchzvHC34/BfHdxIlPfpuFwcaC45c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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