SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd70e77fd9164a6e8e70f3ec3ceb78f787bf965d51d15580a792652381875f101' 
  AND token = 'g4yIT+A5LqV9qEGksVQRCpJXJ6BnTHaEeY9TiSgQqGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00562

JSON explain

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