SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55bbb574e6c04f6a8f49734aae848372dbc83396b40f3694cb0860b72ef28b54' 
  AND token = '7hp01SnwecX5kws8dEZFhPBhbKXZXhQVEHQGbUguzkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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