SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8d87558ad714ba9931e4b69d12c01ef865c423065bea65294278ed989f3a186' 
  AND token = 'yDoL3JBFyPXSREbQD42Rg+uaLpBuHQtzZkgBmDZ/6lk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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