SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ab72f45b583efd31844042ce2221c050dabe340147d71b165afe550479a3ee6' 
  AND token = 'bQEQqU5aOpEmPHZS1e60v+2hYv7fXUzBKjdPtqH3B60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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