SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9352f8fbd667bbd4616d4abc30d5921c5429a35a35df640a0cd6171055c58738' 
  AND token = 'UROgefFyVXu2OLt5htwZz+tkibW2793HVdAx1acO9vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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