SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40991927a4bfb648288866077e60755388a81c2e996dd9dc9e8e00daff483854' 
  AND token = 'GyEfqdgEzFrmXZ5SjsAtshY/B1tvOymwyW+iA567pMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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