SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81fb5f62293852e78f10b63c94667c646e073228578e570fcb7797f2b9045313' 
  AND token = 'gebKltJGpPVA1zoZ+y/UQH3eTkHl3/dH1HB4uMzJIwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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