SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79b798fdaf2f1dcc43f3d8f7418f59180103579ae821622f49274423161fd483' 
  AND token = 'CEEs1wOZYf1vhXubP/OpYu6+vscOPt2rlB5cRJ6qISc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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