SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42f7b2a5a93a67695b22abea15ddcd63487855a52f5b164dc6670295a78cc636' 
  AND token = 'Oh0K6TwCrD8mnQsbKihO+T+KkNfHmS9icbbqaHhQU70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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