SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50e2c413ebdebb2c19cff477af3c3cda5a11a27a8423a501c8953ae35deffeff' 
  AND token = 'Zs87oqMsJXWrhjldLjuLBub7XNqJGpsjDqkmBfK3Sbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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