SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35a7e7c4361f2027fa8095a0d349111238911a4005d8b13dbc279c6c0eca0379' 
  AND token = 'xwmq4FVBuyVhULPj1JHHeJRJPG7Mil+vUQnODNe2KHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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