SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b3e9125f053119b73a7f93565066bbbfbf09d5916418118112970b79d48a0b3' 
  AND token = 'vzpugiAjNimN93RhMGtN8DYZRI1bKVkaElsk4d17mt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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