SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70f13f1901202d233464ef7d2014622fe7a8469345c98adc57af5b33de014f8a' 
  AND token = 'WV98xmsPeL0RGGNHWnJmzmmvh8DrooqiykOgKGCSChI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}