SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3faf204ef5a46364a2cd1692dff3ebacb2c02fdb2f9d5142083a7d8e0eb362a7' 
  AND token = 'rerwkezydGs7z89iqU1/dQ4OQ1CjgEG4NIk7o4FLiS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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