SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe667922457ed929d6ace0d1d561f89e3d3a72e4f586a9c99b8754421846d474' 
  AND token = 'FFFI5OvKZp8YRY1ulfUNldFG30tggXIvh1kMwVPhjOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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