SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9875a5ba22d0d22585b805c743df20e465b54446bdb90e3c877203753315168f' 
  AND token = 'qgyz7PLmnCZjN+wsrpYE+ALPolfZ9YZ5vGF7WTfQvwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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