SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93f327ca87980821049d0bc6b84f851779ad920e1fdf316fc6879da219451dc0' 
  AND token = '+hTSYKUx+G2eXv3Dc1RJYZfJAlB7oEnb4BMESLxARHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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