SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92a50e676c6d4502fd18a19f1e4eeadd48666dbb9ae58a8e38f851fd22377716' 
  AND token = 'tuSS6TzrRFeezTYBUMn8zqty9c10jT4WeUcmL4XU0wY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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