SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f86293c3b0981e9d356c7850197b846006ffac535fa0724759289327376c193' 
  AND token = 'FVpPvlBoI7cK59wjlZrfaH5YKYLPvPmZTG13AuJMl0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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