SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2f41ac4e89e3bf2e827a5b1e64066fb9be9241b9cfba2ad4a00396d9a5aa27a' 
  AND token = 'SeutgBnNCEaOyaLwAjGY86LZY4M/Td1HMIlBx1EmyIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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