SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e51148da899108205027872a05996d2ab00fa7ec0c764977de32bcedd47cf58d' 
  AND token = 'Oj/QciyRxegXtd9kAQhmAJR06vYEDpAAhndGOQvgUNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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