SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7285352af0081178319a47a9d3b0ed02e7845bd731515042222a752d52984b4' 
  AND token = 'G6g7dAMgcAuea3v9dFtZCAgic7xgzJCONl3I/ugDVpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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