SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c2fdc876d8c7e39bc1d203256e30e758bc3cc8c662576910020dd98d38ba080' 
  AND token = 'VIaq6/OQE6DhQ6j23UYnfvZD7YzwuIwKl8zMGGC+RJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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