SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f679c46516102acd35d57da4b7a075edaf8180a47c63e17ddcf5c5f04de8c583' 
  AND token = 'Ucpw87wqiNIrOkdwyzna4Fe3fpMkPWMjoUs0FvdG1Vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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