SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '064be47f6af8feb87c826300421dccd6ace1db1a5e5ad1aee7af7866fe5151d3' 
  AND token = '17J4UCijjmeLAQohNkruNKyGWq5828nLPxK9+VoX4+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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