SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '371abc05385bdd98a400d50c2d02493bdbfe856c98809b2d5f315b124c2d9d1c' 
  AND token = 'F2ftCgyrhuZm7O1V20yfxwb3EcjdGAnxqh0QYD9gnuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}