SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '577de4e2433c78f7d51341cae68ba73c5027865ff0e665b0626fcd34d42dc3ca' 
  AND token = 'O2whLzGxohLm6ngPF/alC7jUS8XGLYrYCKRymuMX4xo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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