SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87c957ba50a4214a3710ffeecbe070da15aab43fa1e4dcd7762dc010d2a1269b' 
  AND token = '5VJ/tf+8KPmaMxOwWdklRw9TEYg6Zj25iC062jpI7VQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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