SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f135ea1382e43c05b7992712c4d45800cdd6b2fd6e41d0065ed08bd62483c5d9' 
  AND token = 'EbhAiCcvH5qXl64SoY1FN9IYLbrrW/sqJd973GfqAjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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