SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d523e6350b62507f78682bf7e25495a14a47b55282feb0dfd8b7fc9b80d6f96' 
  AND token = '39LWfqlXWAPW6zYvopnM6jzFCKb5UD43+PSI98QvADM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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