SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12bcd4e2014454e59531770db73f65d4588b8ec96710d633a23847800eae5d01' 
  AND token = 'Iexzu6VUx/iwHu3qK9pcdzaU45tVJ3cWHwaQMBygfjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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