SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2376518e57bf401a0e821ed8f7290f5d8f1663606a5271e5ce5fc464670e83a1' 
  AND token = 'Zz0e9PWmQBOjNwszLarqK3FH/PVY3gGfJY9IEWmNTaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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