SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b935f66b271c020a63c0d72709298976ce4eb36b8c17c36b906aeda9783e6dfa' 
  AND token = '1UFwXiuNgwxM6qFXXGP6TpB8+Yw33dNOhDCevsfpXoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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