SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6ec3f11aefe73062d1aa0f9670740ba2a51505f7ead8ce5e86dde8ddd89bc51' 
  AND token = 'ugNGggl3MVXJ62jxBZ24SRNZt011RC/rVJJwo3hQQ48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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