SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '038c485dde0793bc657ffcdefc216bff8b45c94322062301a8c26c4b87ed8a31' 
  AND token = 'MnMezhBdw8rM8VYlvv7m3ummKjYO7asa/axJQdg/Uok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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