SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c68e8bc3620da72d3e18b5acc915d434886ef4dfcf7f8de61a82c5ad5b3431d4' 
  AND token = 'cBF9LBGZRqH9JGrBVgnweeVBAojAu1Ot15KXUX+EvBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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