SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc1f82af7885c7e1edd436c8b15ac1ab461bf9d38e8e3bc37e26014b8509b7d7' 
  AND token = 'zsz7oZLOP/CuCO6tC3FOXz+Q8J+iuMyKwxllBB1GDog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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