SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '257f08c43f3357f4b5626e6053fda9071a35b06952df09e9b56a5be914501a2d' 
  AND token = 'qA28aM8V9rAKsb8L6/+VFzq6/TiYOCz7oPjCkROQmVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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