SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba792b7002d7a7769f297979a8134f1f4a5ab0e2cf844983482f7f84819a9fe1' 
  AND token = 'I5f4kNKW5+zg+jiMXukqwGUVfHDdcB3qmKwmk/X8EAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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