SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dabba92a949ea74b260700030a3c04d2c773d45ebce6e0f0a18a0934bdac0feb' 
  AND token = 'jpnaTnUnUGgTm4euoW7+uUj2DC3iK7L/0MMQ2pqmNvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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