SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9ba6945c30b6e348642b31143a54428fc1cf775a83c8d6522bc139223794798' 
  AND token = 'L4hCzlgJUdYZOWxgyr4q9OVgami/kUvd6ewH+8IrPcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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