SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f90718d35e30471725eaa2abdb34d9af9803cd71ddfad0efaaf4465c1142a56' 
  AND token = 'RVxuBq8mdakxzqTF21/Bfh5aCzFNo7VR4SBIHxvdlcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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