SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2d12f685aa74b27a4f7885ecf66a998b82a696aa0553b6591afcabd593d7d1f' 
  AND token = 'jzFlJ5zclOQps4dGNNBfeE0u+GZspvqiJOajtqvAqB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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