SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d7afd87afca985e062cca7c579952980420404a6b45e8c3f731a46aae7dc4a5' 
  AND token = 'Vtnz1hL/UtGS6PAQ2aN1WWN2Jzw4MWl7jQpdIja9R34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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