SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9219ba71abec97cd51e8876e8b12a68817ef50169c449805af342c6fa18c05a7' 
  AND token = 'R1w2H+Y2MEj/U3AikxBZP9KGgMcQtV5DsrJpPR/u5qE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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