SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b1915ffc1318657ecd448b59584da404845b88f0af3c40456dd792ecfbe42dc' 
  AND token = 'O/ryjyaScptQ571alVVdmJSMlbIscvsgAQZiFFMFjnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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