SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bd85d93f1c7485b9b3da5677b0d1452d7d0b6d2ac1921754a783c9ec02a4390' 
  AND token = 'GuwoYxk0h8meHpUfMChVEhYm+3AU9HdvAOQAFjRZu/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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