SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd83ab3d90c7a1cf076e13e9ae4202c1ea310d3eba727cedf01a69503020a4261' 
  AND token = 'MfZTBkeB3xSYwX6cd7ccWTutcv31uB7lRfboTuCX9J4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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