SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7efaf1fcd8b278566599b4fb2dfefe6ff8c3887d9d749821042de55a3675795c' 
  AND token = 'zWIwQrfB0AvFGvpKENmHsDoQ1olRcXsFoSVcjfUZ33Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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