SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bb383a80bfcf1e43ad3b064c7e983301dbdca41195c662a540135556c284e8e' 
  AND token = 'Tm2TVqVavaQP0q3Q85DPpki39sgxyKVLRwosBqoz9WM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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