SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '948f4260fb3a70ef728adea1fcd53a0080f4d7856bc6688fc7bbc5299ec0e0a1' 
  AND token = '+BHX/rpOzqCbUO7JnOWnfy+weKmxFWv/gFF2Z4ug+dk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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