SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46a3ff6724d57d6c5f50ee172f838ef3445d8a44b94f625ab1aea8a95b460e11' 
  AND token = 'dHBBpKneIHz3FdXzxovtegYnAl5ejaRhmO4CUXUPZOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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