SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8628550435e741ba8d29599b11b4c2011efcf3d903517c3259856ad0b758d15' 
  AND token = 'Z8A0t/veyloVyg2aY8HyAdVPgoTQ5lSLoVCImNWka68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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