SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '913b11e6a56e1603a5c5d87b1b66f6fe81998bf5b2f7269082b7a35163022871' 
  AND token = 'wK19Iok+TkoISGyMos8ImmgRHcb7aZrLRF5fN2KxzKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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